Experimental study on the degradation mechanism of LaCoO₃-based symmetric supercapacitors

Abstract

Cycling tests for LaCoO3-based symmetric supercapacitors were carried out. The change in the valence state of Co in the electrode surface active material, LaCoO3, before and after the cycling test was investigated by X-ray photoelectron spectroscopy.

A Parchment‐Like Supercapacitor Made with Sustainable Graphene Electrodes and its Enhanced Capacitance by Incorporation of the LaSrCoO3 Perovskite

“…By considering the results obtained from the CV curves, optical absorption, Raman and XPS, we infer that redox reactions are the main charge storage mechanism of the SLG/LSC‐SC device and the redox centers are the oxygen vacancies as well as the Co 3+ /Co 2+ species. Finally, we should mention that the continuous charging/discharging cycles decreases the amount of the Co 2+ species in the electrodes and the Co 3+ species become more abundant, this in turn, reduces the content of oxygen vacancies and makes the redox reactions less efficient for the charge storage [54] . For this last cause, the capacitance retention is lower at the end of 500 charge/discharge cycles.…”

“…Finally, we should mention that the continuous charging/discharging cycles decreases the amount of the Co 2 + species in the electrodes and the Co 3 + species become more abundant, this in turn, reduces the content of oxygen vacancies and makes the redox reactions less efficient for the charge storage. [54] For this last cause, the capacitance retention is lower at the end of 500 charge/ discharge cycles.…”

Polymer/Reduced Graphene Oxide/Lignosulfonate Nanocomposite Films as Pseudocapacitor Cathodes

“…The variation in η c and C ret observed in this study was similar to the trend reported previously. 61 Galvanostatic charge− discharge assays were also performed applying a lower constant current of 0.06 A cm −3 . Under this low current and after 62 h/ 1000 cycles of galvanostatic charge−discharge within a 2 V potential window, the total initial time of the charge−discharge obtained was 146 s (Figure S5, Supporting Information); LEA = 6.49%, C ret = 93.5% and η c = 100%.…”

“…The marginal variation observed in η c and C ret can be attributed to a combination of multiple factors such as (i) slight change in the ambient temperature during measurements, (ii) volume changes affecting the electrode surface roughness during the charge–discharge measurements, consequently impacting the contact area between the electrode and the electrolyte, and (iii) intense polarization of the electrodes at a high applied potential (2 V) used in this work, which could affect reversibility and stability of ionic charges. The variation in η c and C ret observed in this study was similar to the trend reported previously . Galvanostatic charge–discharge assays were also performed applying a lower constant current of 0.06 A cm –3 .…”

Investigation of supercapacitor cyclic degradation through impedance spectroscopy and Randles circuit model

“…5 Measurement of "equivalent series resistance (ESR)," along with capacitance, is a general way to observe and predict the "end of life (EoL)" 6 of super capacitors. The degradation mechanism, which eventually corresponds to EoL, 7 mainly depends on the changes occurred in active surface area of electrodes, 8,9 in association with formation of gaseous products as outcome of electrolyte degradations, followed by saltprecipitations. 10,11 To account the degradation mechanism up to a significant extent, electrochemical impedance spectroscopy (EIS) is one of the most preferred methods.…”